#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <iostream>
#include <vector>

using namespace std;

struct ListNode {
    int val;
    ListNode* next;
    ListNode(int x) : val(x), next(NULL) {}
};

struct TreeNode {
    int val;
    TreeNode* left;
    TreeNode* right;
    TreeNode(int x) : val(x), left(NULL), right(NULL) {}
};

class Solution {
   public:
    int maxDepth(TreeNode* root) {
        if (root == NULL) return 0;
        return max(maxDepth(root->left) + 1, maxDepth(root->right) + 1);
    }
};

int main() {
    cout << "Hello, World!";
    // Solution()
    return 0;
}